Electrolytic decomposition of solutions.



` f UNITED STATES PATENT OFFICE.

CLINTON RTOWNSEND, or wAsHING'roN; ms'rm'r or COLUMBIA, .assIGNon To THE .tween the DEVEIIOPIIENT` ANI) FUNDING COMPANY, 0F

oF NEW JEnsEY.

:NI-:w Yoan, N. Y., a'cononaTIoN ELEcTnoLYTIc nEconPo'srrIoN. or aeLIITIoNs.

1 peana-aan of nemer ment. i A Patented oet. 18, 1910.

Application mea prix 12, 1902, semi N9. massa. Renewed lama 9,1909. serm No. 482,401.

To all whom it may concern.' i

Be it known that I, CLINTON 1 TowNrA SEND, a citizen of the United States, residingv at Washington, in the'District of Columbia, have invented new and useful Im rovements in Electrolytic Decomposition-oP Solutions, of which the following is a specification.`

This invention relates to vthe electrolytic decomposition of solutions, and particularly to a process of Collecting the products of such decom osition.V

I will descri e the process with reference tothe electrolytic decomposition of sodium chlorid solution, it being understood that such solution is a type or illustration onlyA and that the thereto.4 Accordin products o `the electrolysis, or ay secondary product resulting from the action of the primary product upon the electrolyte, or

invention is not restricted upon the immiscible liquid hereafter men-` tioned, iscollected in,under, or above an' 'i immiscible liquid, which. serves several im- 25 Y portant functlons.

As a specific example ofthe process,' I

will describe the .electrolysis of sodium chlorid solution to produce caustic soda and jchlorin, referring' tothe' accompanyi/ng,"y

drawings, wherein:

of one Jtypepof cell; Fig. .2. -isa sectional de?.

tailupon Aa. large'rsc'a showin struction "of the diaphragm,' cat retainingl plate; and Fi one con- -3 is a transverse .modified form ofcell. w l Referringto Fig. 1, thecell comprises a central compartment B, containingl ananode vertical' section .off the ower, portion .of a

D and one or more lateral'or cat, ode com-Il partments C, shown as two in number, sald F F', are diaphragme ofasbestos or other" suitable pervious material. si1pported. be'-` perforated 'sheet orl wire gauze E,

and the' rforated or pervious'plate G. As

shown, E, are'of metal and constitute the' cathode's of the'cell. The plates G, which may beof hard rubber or -of earthenware,

cathode.

ployed for heating fthe cell to maintain its temperature at any .desired point. Asillnstrated, theicathode compartments to my invention,` one Vof the with amain conduit from which the-solution' may be. withode, and

from. thevertical, but suchv inclination Ais notl essential. f M represents a sheet of metal, as iron, adjacent and approximately parallel to the v- This late terminates a slight dista-nce above the'bottom of the cathode compartment and below its top, for a 'pur pose hereinafter described..

nonconducting and serve Ito plroper; they may, of 5t Hv is a coil suitably connected and.' eml' or cooling the liquid in .C are somewhat deeper than'the central or anode compartment, and are provided with valvefregu ated .drai l ending to the tan L. dfawnv asdesired.- v

V In operation, the central compartment is 'filled with'sodium` chlorid'solution, and a through this compartment fr om' below upward., the inlet I and the outletJ being provided to this end.' The lateral ompart-` ments are `filled to l a `higher on lower level with a liquid whichis substantially immiscible with water or a ueous ysolutions and inert toward the pro ucts of electrolysis liberated in.l contact therewith, or' the secilpescommunicating vcontinuousflow is preferably maintained ondary products resulting'froin `the oxida' tion or otherchemical modification-of said ingoils'f may be' ,taken as lan example. pon' the passage of the current .chlorinis liberated at the anode and sodium at the cathode. The chlo'rin vescapes from the? cell and may be collected and used as desired.

f'oducts.: `Of such liquids, thenon--saponiinp'art or entirely oxidized. by the solution The -caustic solution so' "The sodium is set free at the ca'thodeand is 10o 'cathodean lstrong circulation of the oil, which further aids in detaching the` globules of caustic solution, thereby removing them quickly.

from the field of the electrolytic action.

.The chief advantages due to the use of a' liquid immiscible with the electrolyte` for the purpose of collecting a product of the electrolytic decomposition thereof may be stated as follows:

(1) The roduct is formed and collected under'a seal of said immiscible liquid and is thereby protected from all effects due to the 'Contact of atmospheric gases. In the case of caustic soda', for instance, the sealing liquid .prevents 'the production of' sodium carbonate; it also prevents the production ofcarbonates of such metalsas calcium and magnesium which may be present in an un- -puriedjbrine and which would act to ob- Astructthe diaphragm andfgradually to reduce its poros1ty; 1t also 'prevents levaporation ofthe' liquid which carries the product in solution and consequent deposition therefrom in the diaphragm or on the cathode of tlieless soluble' constituents.

Itefectsl the positive removal of the product from l'the electrode, an effect prob- I ably due-in part at least to the difference in l into another is dependent upon the time the adhesive power of the two liquids, (as, for instance, the caustic solution and the mineral oil), for the material of the electrode. l'For instance,oil adheres closely 4to such surfaces, -and it follows lthat the caustic solution, being unable to displace the oil, assumes at once the form of a4 lobuleV and freely detaches itself from t e surface. Since the amount of diffusion of one li uid uring which they remain in contact, this rapid removal of the caustic 'through'the agency of the` oil is most effective 1n preventing diffusion of the caustic into the liquid in the anode compartmen (3) This removal of the caustic from the cathode is further aided by the fact that the hydrogen, which isa product of the reaction between the sodium and thewater of the brine, and which is set free concurrently with the .production of the caustic, is liberated under the'hydrostatic ressure of the oil' instead of merely expandiing into an atmosphere. The hydrogen is compressed into rbubbles which acquire apositive energy and direction of movement and greatly assist in `detaching globules l of caustic;

(4) The hydrogen, 'moving rapidly upward between the cathode and theY plate M as before mentioned, impartsla rapidv move.- inent of circulation to the oil, which causes the oil effectively and positively to strip from the cathode the particles or globules of caustic solution. This rapid and useful movement of circulation is effected automatically, and without extraneous assistance,

by the escaping hydrogen. The immiscible liquid therefore, operating through its' own adhesion to the cathode surface, through the ydirection which it gives'v to the bubbles of hydrogen, and through its rapid movement of circulation, eifects a practically instantaneous removal of the caustic from the surelectrolysis.

(5) The removal of the 'caustic from the cathode being effected in part by the hydrogen bubbles escaping under the oil and in part by the stripping action of the circulating oil thereby induced, as above described, it follows that an increase of current density, lby which `both of these avorable elects are increased, will operate ad v antageously within certain limits. 'In practice I find that I am enabled to utilize current densities equal to or exceeding one ampere per square inch oflcathode area with a high degree of efficiency, thus giving tothe apparatus a very large capacity.

(6) Durin the relatively slow movement o the oil-in the large compartment between the plate M andthe wall A, the caustic carried by the oil is permitted to lower portion of the cell and in thedrainage system, whence it is Withdrawn as desired. The caustic is thusv automatically deposited as formed out of the circulating path of the loil and out of the field of electrolytic action,

and is positively insulated from the electrolytic eld. f

(7) The'oil further acts in a marked degree to protect the diaphragm from the roducts of the electrolysis. I nd that a gbrous material of vegetable or animal origin may be employed and that the lm ofoil which covers or coats the ber serves to a large extent to revent contact therewith of the products of) electrolysis, and hence to prevent their corrosivel action.I

. (8) The oil affords a convenient means for regu through the diaphragm and hence the coricentration of caustic solutionsproduced at any particular current density. By'ra'ising lface of the cathode and from the field of downward Y separate therefrom and is deposited inthe ating the rate ofow of the electrolyte or lowering the'oil level the amount of percolating liquid may be decreased or increased at will, and this effect may be supplementedy by a variation 1n the level of the liquid in the anode compartment. If the rate'o flow through the diaphragm be greatly diminished the caustic 1s seen to be detachedfrom the cathode in the form of lflakes orv flocculent masses or particles.

(9) The oil serves to positively .support-l the diaphragm and particularly those portions of the same which lie `between the meshes of the cathode and which do not therefore 'derive support therefrom; the tendency of the diaphragm to yield to the pressure of the liquid in the anode compartment and to become perforated is thereby obviated.

(l0) The hydrostatic pressure of the anode liquor varies from top to bottom of the diaphragm, and hence the percolation through portions of the diaphragm at different levels would vary through wide limits in the absence of a balancing hydrostatic pressure. The effect of the balancing or partially balancing hydrostatic pressure of the oil is to compensate in partfor such differences and 7 to equalize the flow through different portions of the diaphragm.

(11) The heating or cooling means for varying the temperature of the oil and hence of the 'electrolyte afford a convenient means for control in this respect.

It is to be understood that the foregoing statement of advantages is merely illustrative, and is not to be construed as in any way limiting the scope of the process as setforth in the claims.

In Fig. 3 I have indicated a construction wherein both anode D and cathode E, are placed in contact with an immiscible liquid and the anode as well as the cathode products'are collected in, under, or above -such liquid.

In o erating the cell I have noted a very marke storage effect, the yield at first being low but rising rapidly to figures closely ap` proximating those required by theory. On ceasing to pass current through the cell, a strong secondary current a pears, ap arently due to the oxidation otP sodium w lich had been deposited upon the cathode and protected from oxidation. This secondary current persists for some time and caustic soda solution is delivered from the cell during the whole of such'period. In case it is desired to interrupt the passage o f current the electrical connections as to cause this secondary or more cells to pass through other cells, whereby such current is emplo ed to produce a useful effect. Such proce ure should not be permitted to continue too long however as some oxidation or solution of the cathode may occur.

1. The process of electrolyzing solutions, which consists in passing an electric current through the' cellmay be so changed current from two through the solution to an electrode, and recovering a product of electrolysis by means of a liquid which is substantially immiscible with water or an aqueous solution and inert toward said product, as set forth.

2. The process of electrolyzing solutions, which consists in passin an electric-current through the solution an a diaphragm to an electrode, and recovering a product of elecelectrode, whereby a forth.

ward said pro trolysis by means of 'a non-saponifying oil,

as set forth.

4. The process of electrolyziiig solutions, which consists in interposing a diaphragm and a pervious electrode between a body of the solution and a body of a liquid which is substantially immiscible with wat/er or an aqueous solution and inert toward a product of the electrolysis, and passing an electric current through said solution and diaphragm to said electrode, whereby said product is removed from the field of electrolysis, as

set forth.

5. The process of electrolyzing solutions, which consists in interposing a diaphragm and a pervious electrode between a body of the solution and abody of a non-saponiying oil, and passing an electric current through said solution and diaphragm to said product `is removed from the field of electrolysis, as set forth.

6. The process of electrolyzing solutions, which consists in passing an electric current through the solution to an electrode, recovering a product of electrolysis by means of a liquid which is substantially immiscible with water or an aqueous solution and inert toward said product, and circulating said liquid in contact with said electrode, as set 7. The which consists in passing an electric current through the solution to, an electrode, recovering a product of electrolysis by means of a liquid which is substantially immiscible with water or an aqucous solution 'and inert touct, and circulating said liquid in Contact with-said electrode by means of a gaseous product of the electrolysis, as set forth.

8. The process of which consists in passin through the solution and electrolyzing solutions, an electric current a diaphraffm to an electrode,I recoverin sis by means of a iquid which is substan tially-immiscible with water or an. aqueous process of electrolyzing solutions,

a productY ofc ectroly-v solution and inert toward said product, 'and circulating said liquid in contact with said electrode, as set fort-h.

9. The process of electrolyzing solutions, which consists in passin an electric current through the solution and a diaphragm `to an electrode, recoverin' a. product of eledtrolysis by means of a Iiquid which is substantially immiscible with water or an aqueous solution and inert toward said product, andcirculatin i saidliquid Aincontact with vsaid I product-of.-

electrode y meansl of a gaseous the electrolysis, as 'set forth.

10. -The process of electrolyzingv solutions,

which consists in passin an electrlc current through the solutlon'an a diaphra my to'an electrode, recovering a product of e 'ectroly' sis by vmeans fof a quid which is substan- 4 vtially immiscible with water or an aqueous .,through'the solution and a'diaphragm to an electrode,recovering a product of electrolysis solution and Ainertitoward said product, and

circulating -s-aid liquid ra idly upward along saidelectrode and Slow y downward Aat a distance from said electrode, as 'set forth.

11'1. The process of electrolyzing'solutions, which4 consists in passino' anl electric current by means luffa liquidl which issubstantially `immi'scible rwith water or an. aqueous soluvtion and inert toward said product, and circulating said-liquid rapidly upward along saidfelectrode and slowly downward at a distance from said' electrode by means of a asous product ofthe electrolysis, as set or 1.-

.12.' The process of electrolyzing solutions, which consists in interposing a diaphragm and'. a peryous electrode between a bod of the solution and the bod of a liquid which is substantially immiscib e 4with water or an aqueous solution and inert toward aproduct of the electrolysis, passing an electric'current through said solution and diaphragm .to said electrode, whereby said product is t removed from the field of electrolysis, and

controlling the temperature of the -electrolyte by'suitably varying the temperature of said liquid, as set forth.

In testimony whereof I aiix my signa:

ture in presence of two witnesses.

CLINTON P. rrowrusnu'n.l i

Witnesses z' EUGENE A. BYnNEs, Y v CLAUDE I. PARKER. 

